Secondary electric clock



(No Model.)

D.- P. SWEET.

SECONDARY ELECTRIC CLOCK. No. 253,783. Patented Feb. 14,1882.

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' suitable circuit-breaker actuated by chronome- UNITED STATES PATENT OFFICE.

D. FRED SWEET, OF HASTINGS, MICHIGAN.

SECONDARY ELECTRIC CLOCK.

SPECIFICATION forming part of Letters Patent No. 253,783, dated February 14, 1882.

Application filed July 23,1881. (No model.)

To all whom it may concern:

Be it known that I, D. FRED SWEET, of Hastings, in the county of Barry, and in the State of Michigan, have invented certain new and useful Improvements in Secondary Electrical Clocks 5 and I do hereby declare that the following is a full, clear,and exact description thereof, reference being had to the accompanying drawings, and to the letters of reference marked thereon, making a part of this specification.

This invention relates to certain improvements in secondary electric clock or time movements to be placed in electric circuit with a ter or clock mechanism operating as a prime motor to produce an intermittent electric current whereby the secondary clock or time mechanism will be operated synchronously with the prime motor; and the invention has for its objects to provide certain improved means, whereby the minutehand wheel of the secondary clock or time mechanism may be operated by the magnetization and demagnetization of an electro-magnet produced by the intermittent electric current established through the medium of the prime motor. These objects I attain by the apparatus illustrated in the accompanying drawings, in which- Figure 1 represents a top view of my improved apparatus, and Fig. 2 a longitudinal vertical section thereof.

The letter A indicates the frame of the apparatus, and B an electro-magnet secured to a transverse bar, 0, forming part of the lower portion of the frame at one end.

The letter D indicates a lever attached to a transverse rock-shaft, E, journaled in bearings F at opposite sides of the frame. To said rockshaft is also secured a short arm, G,which carries an armature, H, arranged to vibrate directly over the poles of the magnet in the usual manner. The rear end of the lever is provided with a slot, I, formed by bending the said end forward, or otherwise, and in said slot is pivoted a bent pawl, K, which operates the minute-wheel K, as hereinafter more fully described. The upper surface of the arm G'forms a bearing for a spring, L, which throws the armature from the poles of the magnet when the same is demagnetized. The upper 'end of the pawl K extends rearwardly, and when the lever is elevated is brought into contact with a pin or stop, M, so as to hold the lower end of said pawl forward in one of the notches of the minute-hand wheel when the rear end of the lever D is elevated, and thus prevent the minute-hand wheel from being carried too far by the impulse given it by the pawl,the pressure upon the pawl being in exact proportion to the strength of the battery-that is to say, as the battery power is diminished the pressure upon the pawlis diminished, and vice versa, and consequently the pawl will bend in proportion to the strength of the battery, thus equalizing its action throughout the variations in the strength of said battery, and securing uniformity and exactness in the operation of the secondary clock mechanism. This is owing to the reason that the magnetism of the magnet increases or diminishes with the strength of the battery and attracts the armature H with more or less force.

The letter N indicates a detent secured to the lever D, which engages one of the notches of the minute-wheelwhen the circuit is broken and holds the said wheel from shifting, the said detent N dropping into the ratchet when the armature H is released and the long lever D dropped, and being raised out of said ratchet as the long arm of said lever is elevated by the attraction of the armature.

It will be perceived that the spring L is peculiarly bent, so as to bear against the arm Gat the extremity of said spring, the said extremity resting near the fulcrum of the arm when the circuit is broken, and exerting but slight pressure, and to bear to the rear of the fulcrum when the circuit is closed, thus bringing the full force of the spring upon the lever to lift the armature at the break of the circuit when the attraction is greatest and overcome the attraction of the residual magnetism in the cores.

Having thus described my invention, what I claim, and desire to secure by Letters Patent, 1s-

1. In a secondary clock or time mechanism adapted to be operated by an intermittent electric current established through the medium of a prime motor, the combination,with an electro-magnet, of a vibrating lever carrying an armature and a bent pawl, the latter being pivoted to the rear end of the lever, and 2t pin when the circuit is open, substantially as and adapted to bear upon the upper end of said for the purposes specified.

pawl and press the same into contact with the In testimony whereof I affix my signature,

ratcheted minute-hand wheel, substantially as in presence of two witnesses, this 23d (lay of 5 and for the purposes specified. July, 1881.

2. In combination with the lever carrying the armature, the electro-nmgnet, and the ratcheted minute-hand wheel, the detent secured to Witnesses:

the said lever and adapted to engage the J. J. MCCARTHY,

1o ratchet-s of the said wheel to hold the same (J. A. NEALE.

D. FRED SWEET. 

